The recovery of tritium by the decomposition of tritiated water in middle or high level is considered to be necessary for the handling of fuel for nuclear fusion or for the reprocessing of spent fuel used in the future, however, presently we do not have an established process in Japan. In the United States of America, a process for reducing steam with an activated metal such as uranium is now used, however, a periodical replacement of the metal is required for achieving a continuous operation because the metal is consumed with the reaction. An operation for replacing an apparatus for radioactive substance is in danger because of contamination and the like. Also the material removed must be treated as radioactive waste, and in addition, uranium metal is very expensive and is difficult to handle for it is a nuclear fuel material.
A process for decomposing tritiated water by using a solid polymer electrolyte has been tried in the United States, however, organic materials have been found to suffer from radiation damage as result of the disintegration of tritium, and therefore the process has not yet been put into practical use.
The electrolysis of water using an alkaline solution is possible in principle, however, since the tritium inventory required in the form of an electrolyte in the apparatus is extremely large, such electrolysis is not practical as a process for treating tritium which is expensive and high in specific activity, and therefore, this process has not been tried.